Accurate rendering of input media with respect to color is an important criterion for digital imaging devices, such as flatbed and film scanners. Input media may include documents, photographs, films and other items that can be electronically captured by digital imaging devices. The color accuracy of a digital imaging device depends on the color correction computations performed by that digital imaging system to correct the color information in the captured images to accurately reproduce the original images on the input media. Color correction computations may involve the use of look-up tables, or linear or non-linear matrix techniques to modify the raw color signals, e.g., RGB signals, of the captured images such that the colors of the captured images are an accurate reproduction of the input with respect to colorimetric or perceptual match.
In general, the color gamut of raw color signals captured from a particular input medium depends the media type, as well as the digital imaging device that captured those color signals. Thus, the color gamuts of captured image signals from one media type are different from the color gamuts of captured image signals from another media type even if the same digital imaging device is used for both media types. As an example, the color gamuts of offset printed media differ from the color gamuts of inkjet printed media. Consequently, even if the filter responses of a digital imaging device are compensated by the color correction computations, the color accuracy of the digital imaging device can be significantly reduced when the media type is not taken into consideration. Thus, the color accuracy of a digital imaging device can be increased by tuning the color correction computations based on the media type of the input media.
Some conventional scanners utilize software that allows the user to select the input media type from a list of predefined media types. As an example, the predefined media types may include high-gloss photos, offset media and coated media. Depending on the user input, customized color correction computations are performed on the captured color signals in accordance with the selected media type, which increases the color accuracy of the scanners.
Although the user input method utilized by the conventional scanners may be appropriate for high end users, the user input method is not appropriate for ordinary users, who may not bother to select the media type, if such selection is made available in an accompanying software. For these ordinary users, the increased color accuracy derived from the media-dependent color correction computations is negated by user neglect or user interface design.
In view of the above concern, there is a need for a system and method for color correcting digitally captured images of input media based on automatic determinations of the media types.